ORGANIC GEOCHEMISTRY OF BARENTS SEA PETROLEUM: THERMAL MATURITY AND ALTERATION AND MIXING PROCESSES IN OILS AND CONDENSATES
The petroleum system in the Barents Sea is complex with numerous source rocks and multiple uplift events resulting in the remigration and mixing of petroleum. In order to investigate the degree of mixing, 50 oil and condensate samples from 30 wells in the SW Barents Sea were geochemically analysed b...
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crwiley:10.1111/jpg.12637 2024-06-23T07:51:37+00:00 ORGANIC GEOCHEMISTRY OF BARENTS SEA PETROLEUM: THERMAL MATURITY AND ALTERATION AND MIXING PROCESSES IN OILS AND CONDENSATES Lerch, B. Karlsen, D.A. Matapour, Z. Seland, R. Backer‐Owe, K. 2016 http://dx.doi.org/10.1111/jpg.12637 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fjpg.12637 https://onlinelibrary.wiley.com/doi/pdf/10.1111/jpg.12637 en eng Wiley http://onlinelibrary.wiley.com/termsAndConditions#vor Journal of Petroleum Geology volume 39, issue 2, page 125-148 ISSN 0141-6421 1747-5457 journal-article 2016 crwiley https://doi.org/10.1111/jpg.12637 2024-06-13T04:22:29Z The petroleum system in the Barents Sea is complex with numerous source rocks and multiple uplift events resulting in the remigration and mixing of petroleum. In order to investigate the degree of mixing, 50 oil and condensate samples from 30 wells in the SW Barents Sea were geochemically analysed by GC‐FID and GC‐MS to evaluate their thermal maturity and secondary alteration signatures. Saturated and aromatic compounds from C 14 –C 18 and biomarker range (C 20+ ) hydrocarbons were compared with light (C 4 ‐C 8 ) hydrocarbon alteration and maturity signatures from a previous study. The geochemical data demonstrate that petroleum generation occurred from the early‐ to late‐oil/condensate window, correlating to calculated vitrinite reflection values of between 0.7%R c and 1.9%R c . Two maturation traits are in general present in the oil samples analysed and indicate mixing of petroleum phases: a C 20+ fraction which represents a possible “black‐oil ‐related” signature; and a C 20‐ fraction, which is probably a more recent oil charge. However, maturity variations are less pronounced in condensates, which in general exhibit higher generation temperatures than oils but are influenced by severe phase fractionation effects. The samples are characterised by diverse biodegradation signatures including depletion of C 15‐ saturated compounds, almost complete removal of n‐alkanes, elevated Pr/n‐C 17 values, high 17α(H), 25‐norhopane content, and a reverse trend in methylated naphthalene distribution. However, the presence of the more recent, unaltered light hydrocarbon charge together with the oil with a palaeo‐biodegraded signature is clear evidence that mixing has occurred. A cross‐plot of C 24 ‐tetracyclic terpane/C 30 αβ‐hopane versus C 23 ‐C 29 ‐tricyclic terpane/C 30 αβ‐hopane can be used to discriminate between Palaeozoic/Triassic and Jurassic‐generated petroleums in the Barents Sea region, since it appears to be maturity independent. Article in Journal/Newspaper Barents Sea Wiley Online Library Barents Sea Fid ENVELOPE(-65.939,-65.939,-68.664,-68.664) Journal of Petroleum Geology 39 2 125 148 |
institution |
Open Polar |
collection |
Wiley Online Library |
op_collection_id |
crwiley |
language |
English |
description |
The petroleum system in the Barents Sea is complex with numerous source rocks and multiple uplift events resulting in the remigration and mixing of petroleum. In order to investigate the degree of mixing, 50 oil and condensate samples from 30 wells in the SW Barents Sea were geochemically analysed by GC‐FID and GC‐MS to evaluate their thermal maturity and secondary alteration signatures. Saturated and aromatic compounds from C 14 –C 18 and biomarker range (C 20+ ) hydrocarbons were compared with light (C 4 ‐C 8 ) hydrocarbon alteration and maturity signatures from a previous study. The geochemical data demonstrate that petroleum generation occurred from the early‐ to late‐oil/condensate window, correlating to calculated vitrinite reflection values of between 0.7%R c and 1.9%R c . Two maturation traits are in general present in the oil samples analysed and indicate mixing of petroleum phases: a C 20+ fraction which represents a possible “black‐oil ‐related” signature; and a C 20‐ fraction, which is probably a more recent oil charge. However, maturity variations are less pronounced in condensates, which in general exhibit higher generation temperatures than oils but are influenced by severe phase fractionation effects. The samples are characterised by diverse biodegradation signatures including depletion of C 15‐ saturated compounds, almost complete removal of n‐alkanes, elevated Pr/n‐C 17 values, high 17α(H), 25‐norhopane content, and a reverse trend in methylated naphthalene distribution. However, the presence of the more recent, unaltered light hydrocarbon charge together with the oil with a palaeo‐biodegraded signature is clear evidence that mixing has occurred. A cross‐plot of C 24 ‐tetracyclic terpane/C 30 αβ‐hopane versus C 23 ‐C 29 ‐tricyclic terpane/C 30 αβ‐hopane can be used to discriminate between Palaeozoic/Triassic and Jurassic‐generated petroleums in the Barents Sea region, since it appears to be maturity independent. |
format |
Article in Journal/Newspaper |
author |
Lerch, B. Karlsen, D.A. Matapour, Z. Seland, R. Backer‐Owe, K. |
spellingShingle |
Lerch, B. Karlsen, D.A. Matapour, Z. Seland, R. Backer‐Owe, K. ORGANIC GEOCHEMISTRY OF BARENTS SEA PETROLEUM: THERMAL MATURITY AND ALTERATION AND MIXING PROCESSES IN OILS AND CONDENSATES |
author_facet |
Lerch, B. Karlsen, D.A. Matapour, Z. Seland, R. Backer‐Owe, K. |
author_sort |
Lerch, B. |
title |
ORGANIC GEOCHEMISTRY OF BARENTS SEA PETROLEUM: THERMAL MATURITY AND ALTERATION AND MIXING PROCESSES IN OILS AND CONDENSATES |
title_short |
ORGANIC GEOCHEMISTRY OF BARENTS SEA PETROLEUM: THERMAL MATURITY AND ALTERATION AND MIXING PROCESSES IN OILS AND CONDENSATES |
title_full |
ORGANIC GEOCHEMISTRY OF BARENTS SEA PETROLEUM: THERMAL MATURITY AND ALTERATION AND MIXING PROCESSES IN OILS AND CONDENSATES |
title_fullStr |
ORGANIC GEOCHEMISTRY OF BARENTS SEA PETROLEUM: THERMAL MATURITY AND ALTERATION AND MIXING PROCESSES IN OILS AND CONDENSATES |
title_full_unstemmed |
ORGANIC GEOCHEMISTRY OF BARENTS SEA PETROLEUM: THERMAL MATURITY AND ALTERATION AND MIXING PROCESSES IN OILS AND CONDENSATES |
title_sort |
organic geochemistry of barents sea petroleum: thermal maturity and alteration and mixing processes in oils and condensates |
publisher |
Wiley |
publishDate |
2016 |
url |
http://dx.doi.org/10.1111/jpg.12637 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fjpg.12637 https://onlinelibrary.wiley.com/doi/pdf/10.1111/jpg.12637 |
long_lat |
ENVELOPE(-65.939,-65.939,-68.664,-68.664) |
geographic |
Barents Sea Fid |
geographic_facet |
Barents Sea Fid |
genre |
Barents Sea |
genre_facet |
Barents Sea |
op_source |
Journal of Petroleum Geology volume 39, issue 2, page 125-148 ISSN 0141-6421 1747-5457 |
op_rights |
http://onlinelibrary.wiley.com/termsAndConditions#vor |
op_doi |
https://doi.org/10.1111/jpg.12637 |
container_title |
Journal of Petroleum Geology |
container_volume |
39 |
container_issue |
2 |
container_start_page |
125 |
op_container_end_page |
148 |
_version_ |
1802642740416086016 |